Transistors, such as metal oxide semiconductor field-effect transistors (MOSFETs), are the core building block of the vast majority of semiconductor devices. Epitaxial stressor regions are frequently used to increase the mobility of carriers in the channels of the MOS transistors, and thereby achieve a corresponding improvement in performance. However, the stressor regions and the substrate material have different chemical properties (e.g., etch rates, oxidation rates, diffusion rates, and the like) that increase the difficulty of integrating epitaxial stressor regions into existing fabrication processes.